Last month there was rejoicing that Joshua Reynolds’s ‘Portrait of Omai’ had been saved for this country at a cost of £50 million. My hat was in the air with everyone else’s. But much less attention has been given to another artwork that is in need of rescuing, one of far greater national and artistic importance: an object that proclaims the birth of the Church of England – and is available for less than a tenth of the cost of ‘Omai’.